Extruder lag?

[dgirard]

First good print!...

After many trials/tribulations with the extruder gears grinding, and a heated bed meltdown I'm finally at a point where I can start calibrating...

I'm seeing some threads then the head moves after extraction, and also having a thread attached to the top of my cube running up to the cold extruder when the print is done...

Getting a bit of blobbing at the start (end?) of each layer, but it seems like some of the other areas may be a bit thin...

One thing I noticed is that there's a lag between the time that the extruder motor pushes the filament (or retracts it) and the reaction of the extruder head....this lag is fairly significant

Is this lag normal?...or do I have some binding or temperature issues?

I'm wondering where my next step troubleshooting should be?

[barnett]

My calibration cube this weekend looked identical to yours only the hair on the inside was thinner. I have identical blobbing at those corners and my flat sides are nice like yours.

I might try lowering hot end from 230 to 215 or so after the first layer. I'm set to jog up in Z when it retracts and I can confirm that my corner blobs happened before each Z jog.

Sorry I don't know an answer (yet).

[Polygonhell]

First good print!...

After many trials/tribulations with the extruder gears grinding, and a heated bed meltdown I'm finally at a point where I can start calibrating...

I'm seeing some threads then the head moves after extraction, and also having a thread attached to the top of my cube running up to the cold extruder when the print is done...

Getting a bit of blobbing at the start (end?) of each layer, but it seems like some of the other areas may be a bit thin...

One thing I noticed is that there's a lag between the time that the extruder motor pushes the filament (or retracts it) and the reaction of the extruder head....this lag is fairly significant

Is this lag normal?...or do I have some binding or temperature issues?

I'm wondering where my next step troubleshooting should be?

Yes lag is normal, it's made somewhat worse by the Bowden tube, but extrusion is about pressure in the hotend and it doesn't change instantaneously with or without a Bowden tube.
The blobs are most likely from the extruder sitting still for too long, make sure your travel and Z speed are set as high as you can, make sure the Retract speed is as high as possible and you are not spending too much time on the retract.
The strings are usually addressed by increasing the retract or reducing the extrusion pressure, you can do the latter by printing slower or by printing with lower layer heights, or with lower extrusion width (general rule for lower layer heights is extrusion width should = nozzle diameter, Slic3r does not do this by default). Many Bowden machines use much lower layer heights that people typically do, I think the Ultimachine defaults to 0.20mm layer height, and I believe Tantilus is 0.15mm.
If that's ABS, dropping the temperature won't help a great deal with strings assuming it already has enough time to cool when printing.
Slic3r really doesn't have anything else you can change to address it.
I find the wipe feature in KisSlicer to be a huge win for quality, and in Cura/Skeinforge the dwindle feature can be used to reduce nozzle pressure prior to a retract.

[kometen]

My cube also looks like yours. I have tried to adjust everything, but it seems to be a problem with the printers. I have played with the feedrate, flowrate, extraction values and so on but nothing seems to remove the strings and blobbings. The problem gets worse when I try to write a model with letters on. It is a mess.

good luck

[v8tony]

what program are you slicing with?

I gave up on Slic3r and I use Cura for just about everything now... even my test cubes come out better... make sure to use A LOT of retraction distance... I'm at 10mm @ 50 mm/sec...

Tony